Different types of moveable barrier operators have been sold over the years and these systems have been used to actuate various types of moveable barriers. For example, garage door operators have been used to move garage doors while gate operators have been used to open and close gates.
Such barrier movement operators may include a wall control unit, which is connected to send signals to a head unit thereby causing the head unit to open and close the barrier. In addition, these operators often include a receiver unit at the head unit to receive wireless transmissions from a hand-held code transmitter or from a keypad transmitter, which may be affixed to the outside of the area closed by the barrier or other structure.
Frequently, it is advantageous for gate operators to have the ability to be hold a barrier in an open position for a period of time before returning the barrier to a closed position. For example, a garage door may need to be opened and held in the open position to allow vehicles or other objects to pass through a garage door. The door needs to be held in the open position for a time period such that all or most vehicles can pass the barrier. In such previous systems, a timer is often used to control the period of time during which the door is held in the open position.
In some previous systems, the expiration period of the timer is adjustable by the installer when the operator is installed. However, in these systems, the expiration period is thereafter fixed and could not be adjusted dynamically to take into account variations in traffic patterns at the barrier as conditions at the barrier changed. For example, this shortcoming resulted in the door having to be opened and closed multiple times when traffic was heavy to allow all of the traffic to proceed through the door. In other situations when traffic was lighter, the barrier might be left open for long periods of time when no vehicles were passing through the barrier, thereby creating security problems.
Some previous approaches adjusted the expiration period of the timer when the number of vehicles passing through the barrier increased or decreased. Although this technique increased/decreased the period of the timer to reflect traffic conditions, it was not effective in adjusting the period for a first set or sets of vehicles that came through the barrier. In other words, the initial sets of vehicles would always be subject to an inadequate pause time period, thereby increasing the possibility of a premature closing of the barrier. This technique also proved inadequate in situations where traffic patterns changed frequently and/or suddenly, for instance, at different times of the day or during different days of the week. Specifically, a substantial amount of time was often needed for the system to determine a traffic pattern change and make the timer adjustment. This amount of time often meant that the traffic pattern might change again before a first adjustment could even be made.